PhysicsJS collision monitoring strategies

strategies-1.js

// If you want to subscribe to collision pairs
// emit an event for each collision pair
world.subscribe('collisions:detected', function( data ){
    var c;
    for (var i = 0, l = data.collisions.length; i < l; i++){
        c = data.collisions[ i ];
        world.publish({
            topic: 'collision-pair',
            bodyA: c.bodyA,
            bodyB: c.bodyB
        });
    }
});

// subscribe to collision pair
world.subscribe('collision-pair', function( data ){
    // data.bodyA; data.bodyB...
});

strategy-2.js

// If extending a body and you want to handle its collision
world.subscribe('collisions:detected', function( data ){
    var c;
    for (var i = 0, l = data.collisions.length; i < l; i++){
        c = data.collisions[ i ];
        if ( c.bodyA.collide ){
            c.bodyA.collide( c.bodyB );
        }
        if ( c.bodyB.collide ){
            c.bodyB.collide( c.bodyA );
        }
    }
});

// mixin to the base body class. Adds a method to all bodies.
Physics.body.mixin('collide', function( other ){
    if ( other ){
        // do some default action
    }
    return true;
});

// bodies have an (overridable) collide function